CAD／CAM技术及应用(8)

CAD／CAM技术及应用

end

if eqsp

h = (xCol(n)-xCol(1))/(n-1);

end

else

h = 1;

eqsp = 1;

end

if any(h < 0)

[xCol,p] = sort(xCol);

yMat = yMat(p,:);

if eqsp

h = -h;

else

h = diff(xCol);

end

end

if any(h == 0)

error('MATLAB:interp1:RepeatedValuesX', ...

'The values of X should be distinct.');

end

% PP = INTERP1(X,Y,METHOD,'pp')

if nargin==4 && ischar(varargin{3}) && isequal('pp',varargin{4})

% obtain pp form of output

pp = ppinterp;

varargout{1} = pp;

return

end

% Interpolate

numelXi = length(xiCol);

p = [];

switch method(1)

case 's' % 'spline'

% spline is oriented opposite to interp1

yiMat = spline(xCol.',yMat.',xiCol.').';

case {'c','p'} % 'cubic' or 'pchip'

% pchip is oriented opposite to interp1

yiMat = pchip(xCol.',yMat.',xiCol.').';